There is a good, free audit tool that can be used to find back links in Bing. Type in landing.semrush.com. It might help. As a side note here is an answer to Enriquelon's question about the importance of "no follow" back links in Bing ranking, I came across this quote in a blog about off-page SEO by Chaitanya Singh regarding Bing's "attitude" on back links and there importance. The statement reads "Bing respects ‘nofollow’ as regards not counting the link in their ranking, however it is not proven whether or not Bing follows the link."